VoiceOver on OSX Sfari does not announce list item referenced by aria-describedby, not when tabbing and not when arrowing: "link - HTML || link - PDF || link - RTF"

iOS 6.1,Safari, VoiceOver (iPad mini)

supported - but confusing

While aria-describedby after a longuish pause, all three links are repeated after the parent list item text "Annual Report 2005-2006" has been spoken, which clearly indicates that this use of aria-describedby is not well supported: "HTML - hyperlink - Annual report 2 zero zero 5 - 2 zero zero 6 - HTML - PDF - RTF"